Configuration
The remote server and tunnel port are configured in /etc/default/sidedoor . SSH configuration files are located in the /etc/sidedoor directory. ~sidedoor/.ssh is a symlink to /etc/sidedoor .

Configure REMOTE_SERVER and TUNNEL_PORT in /etc/default/sidedoor .

Create SSH configuration files under /etc/sidedoor .

authorized_keys : SSH public key(s) to control access to the local sidedoor user.

id_rsa : SSH private key to access the remote server. Can be generated with sudo ssh-keygen -t rsa -f /etc/sidedoor/id_rsa (press enter when prompted for passphrase to leave empty). Needs read permission by the sidedoor user or group, e.g., sudo chown root:sidedoor /etc/sidedoor/id_rsa and sudo chmod 640 /etc/sidedoor/id_rsa . The corresponding public key id_rsa.pub will need to be included in the remote user's ~/.ssh/authorized_keys file.

known_hosts : SSH host key of the remote server.

config (optional): Additional SSH config, see man ssh_config .

Restart the sidedoor service to apply changes.

sudo service sidedoor restart

Recommendations

Lock down the local SSH server by editing /etc/ssh/sshd_config .

Disable password authentication ( ChallengeResponseAuthentication no and PasswordAuthentication no ).